The present disclosure relates to sliding doors or swing and sliding doors of vehicles such as subway carriages, railroad carriages, lift cabins, cableway cabins and the like, and in particular to locking them in the closed position.
Doors of vehicles in which persons are transported must remain reliably in the closed position during travel. It is therefore not sufficient to close them by their drive, but it is rather necessary to provide locking devices for them. Such locking devices should of course automatically engage when the door closes and, in normal operation, be released by the drive at the beginning of the opening movement. It must also be possible for the locking devices to be unlocked by the users in emergency operation, for example in the event of the normal door drive failing, so that the doors can be opened manually as a result.
In the case of door drives in which the door leaf or door leaves is/are moved by a spindle mechanism, it has long been known not to arrange the spindle nut in a rotationally fixed manner at the works but to mount it to be rotatable at least within limits. It is also known to provide the spindle with a radially projecting finger which slides in a connecting link and thus provides the rotational locking, making it possible for the nut to act as a spindle nut. Such a drive is known, for example, from DE 28 19 424 A. In that position of the nut, which corresponds to the closed position of the door, the connecting link has a widened portion or a bend which allows the spindle nut to pivot by a predefined amount under the applied torque. Thus, even when the drive is deactivated, the spindle nut cannot move, as a result of banging on the door leaf, into that angular position in which it can be displaced along the predominant part of the connecting link. The door is locked in the closed position. For emergency actuation, elements are provided which act on the finger of the spindle nut and thus allow the nut to rotate into the position aligned with the deflecting connecting link. In the DE 2819424A document, further locking elements are provided which are activated by the nut moving into the end position formed.
Further locking arrangements of the above type are known in various embodiments from U.S. Pat. No. 5,341,598 A, from U.S. Pat. No. 6,446,389 B, from EP 903 275 A and from EP 452 201 A. In some of those documents, the spindle is designed such that the nut engages by a finger in a thread groove on the spindle, and such that the thread groove has a varying gradient. Others of those documents collectively disclose devices such as that mentioned above.
The above-mentioned locking devices have been substantially proven, but all have the disadvantage that problems can occur in unlocking the locking mechanism. Such problems can occur in the case of overcrowded vehicles, dirty guides, iced-up drives, or door guides and/or drives which have been adjusted to the edge of their tolerances or, as often occurs in rough operation, beyond their tolerances. As can be seen from at least one of the designs described above, the drive force or drive torque for displacing the door leaf is available for providing unlocking. That can, on various occasions, in conditions such as persons leaning against the door leaf as a result of overcrowding, etc., be insufficient to apply the torque required to rotate the finger.
The present disclosure, therefore, relates to a locking device which provides greater forces or torques for unlocking the locking mechanism than for a normal movement of the door leaf or door leaves.
According to the present disclosure, the door drive, which comprises the motor, a transmission and a drive spindle, is provided with a torque dividing arrangement which, when the spindle is fixed and the motor is activated, conducts a resulting reaction torque via a locking transmission to the locking device.
Since the door leaves cannot move further when they reach the closed end position of the doors, their connection to a spindle nut prevents any further rotation of the spindle. The result is that the reaction torque is transmitted to the locking mechanism by the torque dividing arrangement, according to the present disclosure. The locking transmission makes it possible to freely select the active torque, and therefore the active locking and unlocking force, within wide limits.
Torque dividing arrangements have long been known in transmission design, and reference is made here only to the planetary gear set. It is of course also possible to design the dividing arrangement differently. That is, it is possible, for example, to mount the motor itself so as to be rotatable or pivotable, so that the reaction torque causes the motor housing to pivot, and to derive the locking or unlocking action from the movement of the motor housing.
Other aspects of the present disclosure will become apparent from the following descriptions when considered in conjunction with the accompanying drawings.